The present invention relates generally to an apparatus for brewing fresh coffee and, more particularly, to an improved coffee brewing apparatus which employs a modified cylindrical brewing chamber to provide enhanced or accelerated extraction of color, flavor and aroma from ground coffee to provide a high quality coffee beverage in an efficient and consistent manner.
There are many types of apparatus and processes employed for brewing fresh coffee in a commercial environment. One very popular process comprises simply pouring a predetermined quantity of hot water at a controlled rate over a bed of coffee grounds contained within a paper filter or other porous supporting medium in such a manner that the hot water seeps downwardly to engage the coffee grounds and to thereby remove or extract from the coffee grounds the soluble materials. The coffee beverage (water and soluble materials from the coffee grounds) then passes downwardly through the supporting medium and is captured within a suitable container, such as a carafe, mug, cup or the like. The quality of the coffee beverage produced utilizing such a pour-over method is generally very good, but the process is relatively slow because of the relatively long period of time necessary for all of the hot water to pass through the coffee bed and for the coffee beverage to be completely collected in the container. Thus, for example, brewing a pot of approximately one half gallon of coffee utilizing the pour-over process takes between three and one-half to four minutes. In addition, the pour-over method is prone to overextraction of coffee solubles due to uncontrollable and inconsistent water seepage paths through the coffee bed.
Another commercial method of brewing coffee in a more automated manner involves the use of a generally cylindrical brewing chamber which is open at both ends. A piston is positioned above the brewing chamber and a screen-like member is positioned below the brewing chamber. At the beginning of a brewing cycle, the brewing chamber is moved downwardly to sealingly engage the screen-like member and a predetermined quantity of ground coffee is inserted into the brewing chamber so that a bed of coffee is supported upon the screen-like member. A predetermined quantity of hot water is then inserted into the brewing chamber and the piston is moved downwardly in the brewing chamber, thereby forcing the hot water under pressure through the coffee grounds and then through the openings in the screen-like member for the actual brewing of the coffee. A container is positioned below the screen-like member for capturing the coffee beverage. Once the brewing has been completed, the piston is withdrawn from the brewing chamber, the brewing chamber is moved upwardly, and the coffee grounds are removed from the screen-like member. While such a brewing chamber apparatus has the advantage of being able to provide freshly brewed coffee in a relatively short period of time, the quality of the coffee produced utilizing such a brewing chamber apparatus is generally not as high as the quality obtained using the above-described pour-over method.
The present invention applies some of the principles employed in the pour-over coffee brewing method, along with some of the advantages of the automated brewing chamber method, to provide an improved brewing chamber apparatus. With the improved brewing chamber apparatus, coffee grounds are exposed to the hottest water as the water leaves the spout and prior to introduction into the brewing chamber to provide a thorough wetting of the coffee grounds to allow the extraction process to begin as early as possible, and so that the highest temperature water is mixed with the coffee for enhanced dissolving of soluble components of the ground coffee. In addition, the coffee and water are stirred as they move into the brewing chamber to provide a high degree of surface contact between the coffee grounds and the water and to continuously wash the coffee grounds with the portion of the extracting solution or water containing the lowest concentration of coffee solubles. This action operates to accelerate the extraction of color, flavor and aroma from the ground coffee and to reduce the likelihood of overextraction or uneven extraction. As a result, a coffee brewing apparatus made in accordance with the present invention produces a high quality coffee beverage approaching that produced utilizing the above-described pour-over method, but yet provides the coffee beverage in the faster, more efficient manner characteristic of a brewing chamber apparatus to provide a labor time savings to the operator of the brewing apparatus.